Evolutionary thinking/ forms of speciation

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

Evolution

 

Lesson 2: evolutionary thinking

In a certain population, disruptive selection is occurring. In this population, which is most likely to survive?

1. organisms with average traits
2. organisms with extreme traits
3. organisms that sexually select
4. organisms that are small

Effect natural selection on phenotype distribution

Cheetahs nearly became extinct but recovery efforts managed to save them. Now, most cheetahs are genetically identical. This is due to:

1. gene flow
2. the bottleneck effect
3. selective migration
4. random mating

Members of different species do not normally produce offspring due to:

1. differing courtship rituals
2. varying breeding times
3. gamete incompatibility
4. all of these

Who is afraid of snakes (or spiders) and why?

Five processes that lead to evolution

1. Small population/genetic drift: chance will start to play a role
2. Non-random mating/sexual selection
3. Mutation
4. Gene flow: immigration and emigration 
5. Natural selection 

1

4

Properly describing natural selection

1. There is genetic variation in the population caused by mutations
2. Some individuals have a higher chance of survival due to an advantage/adaptation(describe the advantage)
3. The better adapted individuals will reproduce more (higher fitness) 
4. The genes of the better adapted individuals will therefore become more common in the population

Speciation:

1. part of a population becomes separated from the rest of the species.

2. adaptation to different environmental conditions.

3. reproductive isolation. As long as the two groups interbreed they share the same gene pool and remain the same species.

Forms of speciation

Allopatric speciation: reproductive isolation is caused by a geographical barrier

Sympatric speciation: there is no geographical barrier, but something else stopping them from reproducing, for example temporal, behavioral or habitat isolation

learn.genetics.utah.edu

Homework

Fill out the lesson feedback form

Finish the worksheet on mating flies.

Go through the LessonUp for next lesson.